The pewwww gun clip comes from the long tradition of mouth made and cartoon laser noises that creators shorten to pew pew for fake shootouts online. No single film or game is credited as its source, so it spread as a generic soundboard effect rather than a famous quote. Its stretched vowel spelling matches the drawn out pitch, making it easy to search, share and reuse in short form edits, game montages and reaction videos where realistic gunfire would feel too heavy.